It is standard practice, as for instance known from the commonly owned and copending application Ser. Nos. 265,819 and 266,097 of E. Wyzgol as well as from East German Pat. Nos. 129,127 and 215,596, to cut the end off a piece of wire in a wire-drawing mill by means of a drum-type shear. Such an apparatus has two vertically superposed drums rotating about respective parallel axes defining a vertical plane. The drums are formed with helical grooves of opposite hand and at least one of these drums carries a cutter blade. The wire to be cut is fed normally through a guide tube to the nip defined by the drums which are counterrotated. The wire is thus drawn axially inwardly by the drum grooves to the blade where it is cut through.
Complex systems must normally be provided to insure that the downstream end of the guide tube is moved axially at exactly the same rate as the rate of axial advance of the wire engaged between the two drum grooves. Since the wire is moving relatively rapidly, normally around 50 m/sec, it is essential, especially with a thin wire having a diameter of around 5.5 mm-6.5 mm, that the two speeds be perfectly synchronized. Otherwise kinking and subsequent breaking of the wire is likely. Such breakage results in extremely costly down time for the entire drawing/rolling line.
Further complex systems are provided at the downstream side of the pair of cutter drums to separate the cropped end sections of the wire from the good center part. These arrangements also frequently require deflection of the wire through such a sharp angle that kinking and breakage of the wire is likely.